The present invention relates generally to the combination of a rotatable stem and a lock therefore, and more particularly to a valve stem having an electro-mechanical lock to control the manual rotation of the stem.
There are many applications where it is desirable to prevent the unauthorized manual actuation of a rotatable stem. For example, in a nuclear reprocessing facility the manual actuation of valves at the wrong time as a result of accident or sabotage could endanger both material and workers. Accordingly, it is desirable to provide remotely controlled locks on each valve whereby a remote operator or central computer control can enable the valve for manual operation only at a proper time as determined from a schedule. These valve locks should be installable on both new valves and on existing valves to which access is limited to the valve stem coming through the panel of an installation.
A related prior valve is shown in U.S. Pat. No. 3,463,445 Churchill et al. In this patent, longitudinal motion of a valve is provided by longitudinal motion of a handle when a solenoid controlled connection between the handle and valve causes a wedging action to occur. The patent is distinguished from the invention by the type of motion required to open the valve and a design which does not directly couple the handle to the valve.